Montana Statewide Rule

Montana Light Trespass Nuisance Law

Some RestrictionsApplies statewide across Montana (2026)

Key Facts

Private nuisance: MCA 27-30-106
Test: Substantial, unreasonable interference
Civil action: MCA 27-30-303
Remedies: MCA 27-30-305

Last verified: September 5, 2026Source: Montana Legislature

Summary

Montana has no dedicated light-trespass statute. Excessive light spilling onto a neighbor's property is handled as a private nuisance under MCA 27-30-106, with a civil action and remedies under 27-30-303 and 27-30-305. Some cities add lighting ordinances.

27-30-305. Remedies for private nuisances. The remedies against a private nuisance are: (1) injunctive relief to enjoin an activity proximately causing the private nuisance; (2) monetary and nonmonetary resources, if quantifiable, that a court determines are reasonably necessary to abate the private nuisance based on relevant and reliable cost factors and established by clear and convincing evidence. All resources provided under this subsection must be spent to abate the private nuisance itself. (3) damages proximately caused by the private nuisance.

Source: Montana LegislatureView official code

Full Breakdown

Montana has no statewide light-trespass statute. Since the 2025 nuisance revision, light that unreasonably interferes with one owner's use and enjoyment is a private nuisance under MCA 27-30-106. Courts weigh intensity, duration, location, and purpose, and a plaintiff must show substantial interference beyond mere annoyance. A civil action lies under MCA 27-30-303, with damages, abatement, and injunctive relief available under 27-30-305. Cities such as Bozeman, Missoula, and Whitefish have adopted local lighting ordinances with measurable limits. Montana has no statewide dark-sky or outdoor-lighting statute.

Violations & Penalties

A private-nuisance action under MCA 27-30-303 can yield damages, abatement, and injunctions (27-30-305). Local lighting ordinances may add fines, commonly $100 to $500.

Frequently Asked Questions

What counts as actionable light trespass in Montana?

Light that substantially and unreasonably interferes with the use and enjoyment of your property, judged on intensity, duration, and purpose, can be a private nuisance.

Can I get a court order to make a neighbor shield their lights?

Yes. A court may order abatement or injunctive relief under MCA 27-30-305 if you prove the lighting is a private nuisance.

Sources

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